<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>  </title>
    <style>
        .box{
            width: 200px;
            height: 300px;
            background-color: red;
            margin: 50px 0;
            
            border-bottom-right-radius: 200px;
            border: 10px solid blue;
            border-top-right-radius: 200px;
        }

        .box2{
            width: 200px;
            height: 200px;
            background-color: #999;
            border: 100px solid #fff;
            box-sizing: border-box;
            border-right-color: red;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <div class="box2"></div>
</body>
</html>